February, '10] COOLEY : OYSTER SHELL SCALE 59 



The emulsion was made as with kerosene emulsion, excepting that a 

 larger volume of hot water was used. The churning was done with 

 the power sprayer by shutting the valve into the supply pipe and 

 forcing the mixture through the overflow pipe back into the supply 

 tank, A violent churning was so produced. 



Several microscopical examinations made up to the time of hatch- 

 ing showed no apparent results. Examinations made while hatching 

 was under way showed that many eggs had turned light brown and 

 were shriveled and stuck one upon another and upon the bark and 

 sides of the parent scale. Living larvae could be seen vainly attempt- 

 ing to extricate themselves from the adhering mass of eggs. Prac- 

 tically no young attached to the bark and formed scales. Subsequent 

 examinations showed that the treatment had been very effective. No 

 injury was done to the trees. 



2. Undiluted kerosene. 



Designed to test the ultimate killing power of kerosene and not 

 thought of as a practical remedy. 



A considerable number of scales were loosened and dropped to the 

 ground — probably about one third — but the eggs under those left on 

 the tree hatched and the young developed normally. The trees were 

 late in putting out foliage and were injured. 



3. "E-ex" lime-sulfur solution, one part to six of water. 



Eepeated microscopic examinations made up to the time of hatch- 

 ing showed no visible effects on the eggs. Moreover, the eggs 

 hatched in a normal manner, and the empty egg shells could be found 

 under the old scales later in the summer, but very few of the young 

 ever attached to the bark, or, if they did attach, they soon loosened 

 and dropped. The treatment was, therefore, effective and satis- 

 factory. 



We were able to find practically no difference in the results ob- 

 tained from the use of ''Rex," "Niagara" and home-made lime- 

 sulfur solutions, nor were the greater strengths more effective. All 

 showed good and satisfactory re&ults. 



4. "Eex" lime-sulfur solution, one part to eight of water. See 

 results under No. 3. 



5. "Rex" lime-sulfur solution, one part to ten of water. See re- 

 sults under No. 3. 



6. "Rex" lime-sulfur solution, one to six, with three pounds lye 



